Alright, let's work through 78687561 times 88087359 step by step
78687561 × 88087359 = 88087359 × (78687561)
+ 88087359 × 1 that equals 88087359
+ 88087359 × 60 yielding 5285241540
+ 88087359 × 500 producing 44043679500
+ 88087359 × 7000 resulting in 616611513000
+ 88087359 × 80000 that results in 7046988720000
+ 88087359 × 600000 that results in 52852415400000
+ 88087359 × 8000000 giving us 704698872000000
+ 88087359 × 70000000 which equals 6166115130000000

= 6931379434641399
